Florida, United States
In a “shocking” incident off the coast of the US state of Florida, a silky shark (Carcharhinus falciformis) regrew a section of its fin a year after suffering a traumatic injury, researchers have found. The findings about the shark’s so-called super-healing abilities were published in the Journal of Marine Sciences.
What happened?
In June 2022, scientists put a satellite tag on a shark’s dorsal fin to track its migration.
However, a month or so later, the author of the study Chelsea Black, a doctoral student and marine biologist at the University of Miami, received a call from a local diver who saw the shark’s tag along with around 20 per cent of the whole appendage missing and alerted the researchers.
(Photo credit: Josh Schellenberg)
It is speculated that the silky shark either got caught during fishing or one of the most plausible explanations is that humans deliberately removed the tag with a sharp object, according to the study. Black told LiveScience in an email that while the reasons remain unknown, she doubts that whoever did this intended to help the shark.
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She also said that the diver later sent her an image “showing the huge hole of where a tag had been”, adding that she had not expected to see the shark again, as the injury was extensive and given that there was no way to track the animal.
But to her great surprise, the shark showed up 332 days later looking remarkably put together. “It was shocking!” the study author told LiveScience. She added, “My first reaction was relief that the shark was still alive, as that was a traumatic wound that could affect his swimming ability or create a significant infection.”
‘Fin repair’
The study noted that while fin repair in sharks is rather common it is rarely full. In this case, the silky shark, according to the study, regained about 87 per cent of its fin back and was seen swimming normally.
(Photo credit: Josh Schellenberg)
But what makes this incident notable is the fact that this is the first time researchers have observed a silky shark regrowing its dorsal fin and only the second recorded case of dorsal fin regeneration in any shark, according to the study.
When a shark with an oddly shaped dorsal fin was photographed by divers in the same area images were sent to Black for identification and she later confirmed by tag ID number that this was the same animal which was injured a year earlier.
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The researchers, however, cannot determine if this remarkable healing process is due to new tissue, scar tissue growth, or fusion of the wound bordering parts but noted that the new fin has a slightly different colouring.
According to the marine biologist, the new fin could be mostly scar tissue but cannot say it with absolute certainty as nobody has ever dissected a regenerated shark fin.
“While the incident of injury remains disheartening, the outcome has provided an extraordinary opportunity to investigate the healing and regenerative abilities of silky sharks following both natural and human-induced injury,” Black wrote.
(With inputs from agencies)